AK2570 Просмотр технического описания (PDF) - Asahi Kasei Microdevices

Номер в каталоге

Компоненты Описание

производитель

AK2570

Feed Forward APC LSI for LD Module

Asahi Kasei Microdevices 

ASAHI KASEI

[AK2570]

[b] Explanation for the modes and the commands

(1) Self-operation mode

The on-chip ‘Power on Reset’ circuit initializes the data in all registers and sets AK2570 in “Self-operation

mode” automatically at ‘Power ON’. In “Self-operation mode”, AK2570 operates as below and keeps the

emission intensity of the LD module constant by periodically applying the compensation voltage for the Bias-

and the Modulation- current against the temperature drift of the LD module.

In 50msec after the end of the resetting operation at ‘Power ON’, the data in EEPROM (Address =‘1 1111 1111

[EINT memory]’) is transferred to RINT and RATRM registers. Notice that the data in these registers can not

change except the case of executing ‘Power ON’ again or re-writing the data with executing ‘WRITE-REG’

command in “Training mode’.

In “Self-operation mode”, the T-SENSE converts the detected ambient temperature to the voltage. AD2

encodes this voltage to the 8bits digital data and transfers this data to RTMP register. This data is converted to

the EEPROM address and utilized for reading the temperature characteristic data of the LD retained in the

EEPROM. The EEPROM data is transferred to RDA1 ~ RDA3 registers and the output voltage of DA1 ~ DA3

are controlled. It is realized that the constant emission intensity of the LD is independent with the temperature

drift by controlling the Bias- and the Modulation- current for the LD module and the alarm signal for the

weakened LD. This behavior is executed periodically (the period is about 100ms). While operating in

“Self-operation mode”, it is impossible to execute any command except ‘Command for Training mode’.

Power ON

The 'Power on Reset' circuit operates and initializes the data in all registers.

The data for RINT & RATRM registers retained in EEPROM (Address="1 1111 1111") is transferred to REG0 register.

The period is

about 100ms

The data is transferred from REG0 register to RINT & RATRM registers.

AD2 executes A to D conversion for the output voltage from the T-SENSE.

0.6ms

（ typ）

The output data "XXXX XXXX" generated by AD2 is transferred to RTMP register.

The access to EEPROM is executed with referring the data held in RTMP register.

The data for RDA1~2 registers retained in EEPROM (address = "x xxxx xxx0")

is transferred to D31~D16 in REG0 register.

The data for RDA3 register retained in EEPROM (address = "x xxxx xxx1") is

transferred to D15~D8 in REG0 register.

The data in REG0 register is transferred to RDA1 ~ RDA3 registers.

50ms

（ typ）

It is waiting for the next compensatory operation.

Note) REG0 register : This register synsthesizes the 32bits data and temporarily holds the data

when transferring the data from the EEPROM to the registers.

<MS0115-E-00>

6

2001/10

Share Link: